Title

Author

Date of Submission

Spring 2015

Academic Programs and Concentrations

Biology

Project Advisor 1

Bruce Robertson

Abstract/Artist's Statement

The ability to effectively identify predators is crucial for predator avoidance. However, very little is understood about the potential of prey species to identify predators based solely on their vocalizations. This study investigates the potential ability of black-capped chickadees (Poecile atricapilla) and tufted titmice (Baeolophus bicolor) to distinguish high-threat from low-threat predators based only on their vocalizations, and whether the basis of this recognition is in the predator’s pitch or syntax of their voice. Black-capped chickadees and tufted titmice rely heavily on visual cues to identify and respond accordingly to predators, with smaller predators considered more dangerous (“high threat”) than large predators. The normal and digitally manipulated calls of small and large owls were played back in randomized order to birds foraging at 10 different birdfeeders to observe and later analyze vocal and behavioral responses. While birds did not vocally communicate threat to heterospecifics, they flushed sites only during small predator and artificially raised vocalizations, which were higher-pitched treatments. These findings suggest that high-pitched calls, no matter the syntax, are perceived as high-threat dangers to foraging birds, indicating that chickadees and titmice can identify predator vocalizations by pitch.